Hello! I am looking to upgrade my receiver and I am looking at the following units:

Yamaha RXV 3800
Onkyo TX SR875
Denon 3808CI
Pioneer VSX 94txsi

I am currenly on my 3rd Yamaha receiver and have had NO problems over the years. I still like the idea of the front presence channels on the Yamaha, but have a large room and wonder if I could benefit from the THX post processing that the Onkyo and Pioneer offer. I am also intrigued by the Reon HQ processor in the Onkyo as I would be using the receiver as the main hub of my system.